Converging flow joint insert system at an intersection between adjacent transitions extending between a combustor and a turbine assembly in a gas turbine engine

ABSTRACT

A transition duct system ( 100 ) for routing a gas flow from a combustor ( 102 ) to the first stage ( 104 ) of a turbine section ( 106 ) in a combustion turbine engine ( 108 ), wherein the transition duct system ( 100 ) includes one or more converging flow joint inserts ( 120 ) forming a trailing edge ( 122 ) at an intersection ( 124 ) between adjacent transition ducts ( 126, 128 ) is disclosed. The transition duct system ( 100 ) may include a transition duct ( 126, 128 ) having an internal passage ( 130 ) extending between an inlet ( 132, 184 ) to an outlet ( 134, 186 ) and may expel gases into the first stage turbine ( 104 ) with a tangential component. The converging flow joint insert ( 120 ) may be contained within a converging flow joint insert receiver ( 136 ) and disconnected from the transition duct bodies ( 126, 128 ) by which the converging flow joint insert ( 120 ) is positioned. Being disconnected eliminates stress formation within the converging flow joint insert ( 120 ), thereby enhancing the life of the insert. The converging flow joint insert ( 120 ) may be removable such that the insert ( 120 ) can be replaced once worn beyond design limits.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Development of this invention was supported in part by the United StatesDepartment of Energy, Advanced Turbine Development Program, Contract No.DE-FC26-05NT42644. Accordingly, the United States Government may havecertain rights in this invention.

FIELD OF THE INVENTION

This invention is directed generally to gas turbine engines, and moreparticularly to transition ducts for routing gas flow from combustors tothe turbine section of gas turbine engines.

BACKGROUND OF THE INVENTION

In conventional gas turbine engines, as shown in FIG. 1, combustiongases created within a combustor 10 are passed to a turbine assembly viaa plurality of transition ducts 12. In many conventional systems, thetransition ducts 12 extended longitudinally without any offset in acircumferential direction. A row of first stage vanes 14 were used toturn the combustion exhaust gases before being passed to the row oneturbine blades 16. The use of first stage vanes 14 in a turbine assemblyto accelerate and turn the longitudinal combustor exhaust gas flow inthe circumferential direction presented several challenges. The vanes 14and the associated vane support structures were required to have highstrength characteristics to withstand the forces generated in changingthe direction of extremely hot, high pressure gas flow over asubstantial angle in a relatively short distance. The temperature of thegas flow and the heat generated by this turning process also require avane cooling system. The forces and heat involved diminished materialproperties causing cracks to develop and otherwise damage the vanes andassociated support structures.

To accommodate these operating conditions and to provide a more robustdesign, as shown in FIGS. 2-10, the transition ducts 20 directingcombustion gases from a combustor 22 to a turbine assembly 24 wereskewed circumferentially such that the outlets 26 of the transitionducts 20 were skewed circumferentially in the same direction of that thefirst row turbine vanes would otherwise skew the combustion exhaustgases in the circumferential direction. As such, row one turbine vaneswere no longer needed because the exhaust gases emitted from thetransition ducts 20 already included the correct circumferential vector,thereby eliminating the need for the row one turbine vanes. As shown inU.S. Pat. No. 8,113,003, filing date Aug. 12, 2008, issuance date Feb.14, 2012, which is incorporated herein in its entirety, the outlet ofeach transition duct is skewed in the circumferential direction relativeto the inlet of each transition duct. While the transition duct systemof the U.S. Pat. No. 8,113,003 has eliminated the need for row oneturbine vanes upstream of row one turbine blades within a turbineassembly, there exists a need to increase the useful life of the skewedtransition duct system by eliminating areas of high stress, which areshown in FIGS. 6-10.

SUMMARY OF THE INVENTION

A transition duct system for routing a gas flow from a combustor to thefirst stage of a turbine section in a combustion turbine engine, whereinthe transition duct system includes one or more converging flow jointinserts forming a trailing edge at an intersection between adjacenttransition duct is disclosed. The transition duct system may include atransition duct having an internal passage extending between an inlet toan outlet and may expel gases into the first stage turbine with atangential component. The converging flow joint insert may be containedwithin a converging flow joint insert receiver and disconnected from thetransition duct bodies by which the converging flow joint insert ispositioned. Being disconnected eliminates stress formation within theconverging flow joint insert, thereby enhancing the life of the insert.The converging flow joint insert may be removable such that the insertcan be replaced once worn beyond design limits.

For a better understanding of the invention, a coordinate system can beapplied to such a turbine system to assist in the description of therelative location of components in the system and movement within thesystem. The axis of rotation of the rotor assembly extendslongitudinally through the compressor section, the combustion sectionand the turbine section and defines a longitudinal direction. Viewedfrom the perspective of the general operational flow pattern through thevarious sections, the turbine components can be described as beinglocated longitudinally upstream or downstream relative to each other.For example, the compressor section is longitudinally upstream of thecombustion section and the turbine section is longitudinally downstreamof the combustion section. The location of the various components awayfrom the central rotor axis or other longitudinal axis can be describedin a radial direction. Thus, for example, the blade extends in a radialdirection, or radially, from the rotor disc. Locations further away froma longitudinal axis, such as the central rotor axis, can be described asradially outward or outboard compared to closer locations that areradially inward or inboard.

The third coordinate direction—a circumferential direction—can describethe location of a particular component with reference to an imaginarycircle around a longitudinal axis, such as the central axis of the rotorassembly. For example, looking longitudinally downstream at an array ofturbine blades in a turbine engine, one would see each of the bladesextending radially outwardly in several radial directions. Thus, theradial direction can describe the size of the reference circle and thecircumferential direction can describe the angular location on thereference circle.

In at least one embodiment, the transition duct system routes gas flowin a combustion turbine subsystem that includes a first stage bladearray having a plurality of blades extending in a radial direction froma rotor assembly for rotation in a circumferential direction, wherebythe circumferential direction may have a tangential direction component.The combustion turbine subsystem may have an axis of the rotor assemblydefining a longitudinal direction and at least one combustor locatedlongitudinally upstream of the first stage blade array and locatedradially outboard of the first stage blade array. The transition ductsystem may include a first transition duct body having an internalpassage extending between an inlet and an outlet. The outlet of thefirst transition duct body may be offset from the inlet in thelongitudinal direction and the tangential direction. The outlet of thefirst transition duct body may be formed from a radially outer sidegenerally opposite to a radially inner side, and the radially outer andinner sides may be coupled together with opposed first and second sidewalls. The transition duct system may also include a second transitionduct body having an internal passage extending between an inlet and anoutlet. The outlet of the second transition duct body may be offset fromthe inlet in the longitudinal direction and the tangential direction.The outlet of the second transition duct body may be formed from aradially outer side generally opposite to a radially inner side, and theradially outer and inner sides may be coupled together with opposedfirst and second side walls. A first side of the first transition ductbody may intersect with a second side of the second transition duct bodyforming a converging flow joint. The transition duct system may includea converging flow joint insert positioned within a recess at adownstream end of the converging flow joint to form a trailing edge ofthe converging flow joint. The transition duct system may include arecess positioned within the converging flow joint to receive theconverging flow joint insert.

The transition duct system may include an insert attachment systemconfigured to attached the converging flow joint insert to theconverging flow joint. The insert attachment system may include one ormore pins extending into the converging flow joint insert and into theconverging flow joint. In at least one embodiment, the insert attachmentsystem may include one or more pins extending through the convergingflow joint insert and through the converging flow joint. The insertattachment system may also include one or more collars for securing afirst end of the at least one pin.

The transition duct system may also include an internal cooling systemwithin the converging flow joint insert. The internal cooling system mayinclude one or more internal cooling chambers in fluid communicationwith one or more exhaust orifices extending from an inlet in theinternal cooling chamber through an outer wall forming the convergingflow joint insert. The exhaust orifice of the internal cooling systemmay include one or more exhaust orifices extending from the internalcooling chamber to an exhaust outlet at an outer surface facing asurface forming the recess in which the converging flow joint insertresides and one or more orifices extending from the internal coolingchamber to an exhaust outlet at an outer surface facing downstream andaway from the recess in which the converging flow joint insert resides.At least a portion of the cooling system may be contained within a pinforming at least a portion of an insert attachment system configured toattached the converging flow joint insert to the converging flow joint.The pin may include an inner channel having one or more inletspositioned outside of the recess at the downstream end of the convergingflow joint and may include one or more exhaust outlets in fluidcommunication with the internal cooling chamber. The pin may include afirst inlet at a first end of the pin in communication with the innerchannel in the pin and may include a second inlet in a second end of thepin at an opposite end of the pin from the first end.

The converging flow joint insert may include a body formed from an outersection, an inner section and a middle section between the outer andinner sections. The body of the converging flow joint insert may includean outer section, an inner section and a middle section between theouter and inner sections, whereby the middle section has across-sectional area narrower in width than the outer and innersections. The inner section may extend further downstream than themiddle section and the outer section extends further downstream than theinner section. A cross-sectional area at a distal end of the outersection may be larger than a cross-sectional area at a distal end of theinner section.

An advantage of the transition duct system is that the converging flowjoint insert replaces an area of high mechanical stress withintransition duct systems with a converging flow joint insert that resideswithin a converging flow joint insert receiver and is exposed to minimaland possibly no mechanical stress.

Another advantage of the transition duct system is that the convergingflow joint insert removes the sharp narrow geometry and the resultingstress concentrations from the converging flow joint between adjacenttransition ducts and incorporates the sharp narrow geometry into theconverging flow joint insert.

Yet another advantage of the transition duct system is that theconverging flow joint insert is removably and replaceable, therebyenabling the converging flow joint insert to be replaced when worn dueto erosion from high velocity gases.

Another advantage of the transition duct system is that the convergingflow joint insert is supported by a converging flow joint insertreceiver that is formed from a buildup of material at the intersectionof sidewalls proximate to outlets of adjacent transition ducts thatincrease the strength of the walls so they can better resist thepressure loading and distributing the stresses over a larger area,thereby reducing the stress levels and increasing the design life of thetransition duct system.

These and other embodiments are described in more detail below.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form a part ofthe specification, illustrate embodiments of the presently disclosedinvention and, together with the description, disclose the principles ofthe invention.

FIG. 1 is a cross-sectional view of a portion of a gas turbine engine.

FIG. 2 is an downstream facing perspective view of an upper half of aplurality of can-annular combustors coupled to transition ducts.

FIG. 3 is an upstream longitudinal view of a circular array oftransition ducts.

FIG. 4 is a side view of a transition duct relative to row one turbineblades.

FIG. 5 is a top view of a circular array of transition ducts.

FIG. 6 is a top view of a fitting in which two adjacent transition ductsare positioned.

FIG. 7 is a cross-sectional view of the two adjacent transition ducts ofFIG. 6 taken along section line 7-7 in FIG. 6 in which an area of highmechanical stress is identified.

FIG. 8 is a perspective detailed view of the area of high mechanicalstress at the intersection between the adjacent transition ducts takenalong detail line 8-8 in FIG. 7.

FIG. 9 is another perspective view of the area of high mechanical stressat the intersection between the adjacent transition ducts taken alongdetail line 8-8 shown in FIG. 7.

FIG. 10 is a partial perspective view of two transition ducts lookingupstream into the internal passageways of the transition ducts showinghow the adjacent transition ducts next together at the exhaust outlets.

FIG. 11 is an downstream facing perspective view of an upper half of aplurality of can-annular combustors coupled to transition ducts.

FIG. 12 is an upstream longitudinal view of a circular array oftransition ducts.

FIG. 13 is a side view of a transition duct relative to row one turbineblades.

FIG. 14 is a perspective view of a plurality of transition ducts coupledtogether immediately upstream of row one turbine blades.

FIG. 15 is a simplified side view of a transition duct shown in FIG. 10.

FIG. 16 is a perspective view of external surfaces of two adjacenttransition ducts at their downstream ends, which are coupled togetherand including a converging flow joint insert positioned within aconverging flow joint insert receiver at an intersection between twoadjacent transition ducts.

FIG. 17 is a perspective view of the converging flow joint insertpositioned within a converging flow joint insert receiver at anintersection between two adjacent transition ducts.

FIG. 18 is a cross-sectional view of the converging flow joint betweentwo adjacent transition ducts taken at section line 18-18 in FIG. 16.

FIG. 19 is a cross-sectional view of the converging flow joint betweentwo adjacent transition ducts taken at section line 19-19 in FIG. 16.

FIG. 20 is a cross-sectional view of the converging flow joint betweentwo adjacent transition ducts taken at section line 20-20 in FIG. 16.FIG. 21 is a cross-sectional view of the converging flow joint betweentwo adjacent transition ducts taken at section line 21-21 in FIG. 16.

FIG. 22 is a perspective view of internal surfaces of a converging flowjoint insert receiver at a converging flow joint between two adjacenttransition ducts at their downstream ends, whereby the converging flowjoint insert is not contained within the converging flow joint insertreceiver.

FIG. 23 is a perspective view of internal surfaces of a converging flowjoint insert receiver at a converging flow joint between two adjacenttransition ducts at their downstream ends with the converging flow jointinsert positioned within the converging flow joint insert receiver.

FIG. 24 is perspective view a converging flow joint insert at adifferent angle than in FIG. 23.

FIG. 25 is a perspective view of external surfaces of a converging flowjoint insert receiver at a converging flow joint between two adjacenttransition ducts at their downstream ends, whereby the converging flowjoint insert is not contained within the converging flow joint insertreceiver and a downstream internal surface of the converging flow jointinsert receiver is displayed.

FIG. 26 is another perspective view of external surfaces of a convergingflow joint insert receiver, taken from a different perspective than FIG.25, at a converging flow joint between two adjacent transition ducts attheir downstream ends, whereby the converging flow joint insert is notcontained within the converging flow joint insert receiver and anupstream internal surface of the converging flow joint insert receiveris displayed.

FIG. 27 is a perspective view of external surfaces of a non-insert sideof the converging flow joint insert receiver at a converging flow jointbetween two adjacent transition ducts at their downstream ends.

FIG. 28 is a cross-sectional, top view of the converging flow jointinsert taken along section lines 28-28 in FIG. 23, as shown relative toa perspective view of external surfaces of two adjacent transition ductsat their downstream ends, which are coupled together and including aconverging flow joint insert positioned within a converging flow jointinsert receiver at an intersection between two adjacent transitionducts.

FIG. 29 is a cross-sectional side view of the converging flow jointinsert taken along section line 29-29 in FIG. 28.

FIG. 30 is a bottom view of the converging flow joint insert shown inFIG. 29.

FIG. 31 is a front view of the converging flow joint insert shown inFIG. 29.

FIG. 32 is a cross-sectional view of the converging flow joint insertpositioned within a converging flow joint insert receiver at anintersection between two adjacent transition ducts taken along sectionline 32-32 in FIG. 28.

FIG. 33 is a cross-sectional side view of the converging flow jointinsert with an internal cooling system together with alternative outersurface locations showing possible alternative positions of the outersurface in other embodiments.

FIG. 34 is an upstream end view of the converging flow joint insert ofFIG. 33.

FIG. 35 is a cross-sectional view of the converging flow joint inserttaken at section line 35-35 in FIG. 33.

FIG. 36 is a cross-sectional view of another embodiment of theconverging flow joint insert with a different internal cooling systemconfiguration taken at section line 35-35 in FIG. 33.

FIG. 37 is a cross-sectional view of the converging flow joint insertconfiguration taken at section line 37-37 in FIG. 16.

FIG. 38 is a perspective view of an alternative embodiment of internalsurfaces of a converging flow joint insert receiver at a converging flowjoint between two adjacent transition ducts at their downstream endswith an alternative embodiment of the converging flow joint insertpositioned within a recess where the converging flow joint insert doesnot protrude through the outer wall defining the recess.

FIG. 39 is a side view of the converging flow joint insert of FIG. 38.

FIG. 40 is a right side view of the converging flow joint insert of FIG.38.

FIG. 41 is a left side view of the converging flow joint insert of FIG.38.

FIG. 42 is a perspective view of the converging flow joint insert ofFIG. 38.

FIG. 43 is a cross-sectional side view of the converging flow jointinsert of

FIG. 38 taken along section line 43-43 in FIG. 42.

FIG. 44 is a perspective view of a first end of the pin extendingthrough the converging flow joint insert of FIG. 38.

FIG. 45 is a perspective view of a second end of the pin extendingthrough the converging flow joint insert of FIG. 38.

FIG. 46 is a cross-sectional view of the converging flow joint insert ofFIG. 38 positioned within a converging flow joint insert receiver at anintersection between two adjacent transition ducts.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

As shown in FIGS. 11-46, a transition duct system 100 for routing a gasflow from a combustor 102 to the first stage 104 of a turbine section106 in a combustion turbine engine 108, wherein the transition ductsystem 100 includes one or more converging flow joint inserts 120forming a trailing edge 122 at an intersection 124 between adjacenttransition duct 126, 128 is disclosed. The transition duct system 100may include a transition duct 126 having an internal passage 130extending between an inlet 132 to an outlet 134 and may expel gases intothe first stage turbine 114 with a tangential component. The convergingflow joint insert 120 may be contained within a converging flow jointinsert receiver 136 and disconnected from the transition duct bodies126, 128 by which the converging flow joint insert 120 is positioned.Being disconnected on side surfaces eliminates stress formation withinthe converging flow joint insert 120, thereby enhancing the life of theinsert 120. The converging flow joint insert 120 may be removable suchthat the insert 120 can be replaced once worn beyond design limits.

In at least one embodiment, the transition duct system 100 may route gasflow in a combustion turbine subsystem 138 that includes a first stageblade array 104 having a plurality of blades 142 extending in a radialdirection from a rotor assembly 144 for rotation in a circumferentialdirection 146, whereby the circumferential direction 146 may have atangential direction component 148. The combustion turbine subsystem 138may also include an axis 150 of the rotor assembly 144 defining alongitudinal direction 152, and at least one combustor 102 locatedlongitudinally upstream of the first stage blade array 104 and locatedradially outboard of the first stage blade array 104.

The transition duct system 100 may include a plurality of transitionducts 126, 128 coupled together such that the ducts 126, 128 exhaustcombustion gases in a downstream direction together with a tangentialcomponent 148, thereby eliminating the need for a first stage turbinevane row upstream from a first turbine blade row, as found in conventiongas turbine engines. In particular, the transition duct system 100 mayinclude a first transition duct body 126 having an internal passage 130extending between an inlet 132 and an outlet 134. The outlet 134 of thefirst transition duct body 134 is offset from the inlet 132 in thelongitudinal direction 152 and the tangential direction 148. The outlet134 of the first transition duct body 126 may be formed from a radiallyouter side 168 generally opposite to a radially inner side 170, and theradially outer and inner sides 168, 170 may be coupled together withopposed first and second side walls 172, 174.

The transition duct system 100 may include a second transition duct body128 having an internal passage 182 extending between an inlet 184 and anoutlet 186. The outlet 186 of the second transition duct body 128 may beoffset from the inlet 184 in the longitudinal direction 152 and thetangential direction 148. The outlet 186 of the second transition ductbody 128 may be formed from a radially outer side 188 generally oppositeto a radially inner side 190, and the radially outer and inner sides188, 190 may be coupled together with opposed first and second sidewalls 192, 194. When the first transition duct 126 is positioned next tothe second transition duct body 128, a first side wall 172 of the firsttransition duct body 126 intersects with a second side wall 194 of thesecond transition duct body 128 forming a converging flow joint 196. Inat least one embodiment, the first side wall 172 of the first transitionduct body 126 may be configured to be coplanar with a second side wall194 of the second transition duct body 128 when assembled beside thefirst transition duct body 126. Longitudinal axes 270, 272 of the firstand second transition duct bodies 126, 128 may be offset from each otherin the circumferential direction 146.

The transition duct system 100 may also include a converging flow jointinsert 120 extending through an outer wall 202 and positioned at adownstream end 204 of the converging flow joint 196 to form the trailingedge 122 of the converging flow joint 196. The converging flow jointinsert 120 is positioned in a location of high mechanical stress inconventional systems. The converging flow joint insert 120 may bedisconnected from the first side 172 of the first transition duct body126 and the second side 194 of the of the second transition duct body128. Being disconnected, yet positioned to act as the trailing edge 122of the converging flow joint 196 enables the converging flow jointinsert 120 to function without being subjected to mechanical stress. Theconverging flow joint insert 120 may be contained within a convergingflow joint insert receiver 136. The converging flow joint insertreceiver 136 may be positioned at the converging flow joint 196 andconfigured to receive the converging flow joint insert 120. Theconverging flow joint insert receiver 136 may include one or more innerwalls 208 defining at least one insert receiving orifice 210 thatprovides support to the converging flow joint insert 120, as shown inFIGS. 22-26. The converging flow joint insert receiver 136 may alsoinclude one or more flange contact surfaces 212 configured to support aflange 214, as shown in FIGS. 29-37, positioned at a first end 216 ofthe insert 120 to prevent the converging flow joint insert 120 frombeing ingested into a turbine downstream of the transition duct system100. The converging flow joint insert 120 may be removably attachedwithin the transition duct system 100. The converging flow joint insert120 may be coupled to the converging flow joint insert receiver 136 viaa weld or appropriate method already invented or yet to be invented.

The converging flow joint insert 120 may be formed from a body 218 witha flange 214 positioned at the first end 216 of the insert 120 toprevent the converging flow joint insert 120 from being ingested into aturbine downstream of the transition duct system 100. The flange 214 ofthe converging flow joint insert 120 may have a larger cross-sectionalarea than the body 218 of the converging flow joint insert 120. Theconverging flow joint insert 120 may be formed from a first side 260that forms an extension of the first side wall 172 of the firsttransition duct body 126 and a second side 262 that forms an extensionof the second side wall 194 of the second transition duct body 128. Theflange 214 and the body 218 may be a unitary structure. In anotherembodiment, the flange 214 may be coupled to the body 218 via welding,brazing or other appropriate connection mechanism.

The body 218 of the converging flow joint insert 120 may include a firstsection 220 with a uniform thickness from a first side 222 to a secondside 224 opposite to the first side 222 and a second section 226extending from the first section 220 and forming an outer downstream tip228 of the converging flow joint insert 120. The second section 226 hasa nonuniform thickness with a thickness at the outer downstream tip 228being less than a thickness at an upstream edge 230. As shown in FIG.20, the first section 220 of the converging flow joint insert 120 may bepositioned closer to the converging flow joint insert receiver 136 thanthe second section 226. The second section 226 may include a first side231 and a second side 233 that is on an opposite side from the firstside 231. The first and second sides 231, 233 may have a somewhat convexsurface that each replicate the inner surfaces of the first side wall172 of the first transition duct body 126 and the second side wall 194of the second transition duct body 128. The trailing edge 229 of theconverging flow joint insert 120 may have a generally curved shapeextending from the first section 220 towards a distal end 232 of thesecond section 226 to follow the contour of the intersection 124 betweenthe first and second transition bodies 126, 128.

The converging flow joint insert 120 may include an internal coolingsystem 234 within the converging flow joint insert 120, as shown inFIGS. 33-36. The internal cooling system 234 may have any appropriateshape configured to adequately cool the converging flow joint insert 120when extending into the hot gas path at the intersection 124 of thefirst and second transition ducts 126, 128. The internal cooling system234 may include one or more internal cooling chambers 236 in fluidcommunication with one or more exhaust orifices 238 extending from aninlet 240 in the internal cooling chamber 236 through an outer wall 242forming the second section 226 of the converging flow joint insert 120.The second section 226 may include an outer downstream tip 228 of theconverging flow joint insert 120, and an outlet 244 of the at least oneexhaust orifice 238 may be positioned at an outer surface 246 of theinternal cooling chamber 236. In at least one embodiment, the internalcooling system 234 may include a plurality of exhaust orifices 238extending from inlets 240 in the internal cooling chamber 236 throughthe outer wall 242 forming the second section 226 of the converging flowjoint insert 120 to outlets 244 of the exhaust orifice 238 positioned atthe outer surface 246 of the internal cooling chamber 236.

The internal cooling system 234 may include one or more impingementplates 248, as shown in FIG. 35, positioned in the internal coolingchamber 236 and extending from a first side 250 to a second side 252opposite to the first side 250 forming the converging flow joint insert120. The impingement plate 120 may include one or more impingementorifices 254, and, in at least one embodiment, may include a pluralityof impingement orifices 254. In another embodiment,, as shown in FIG.36, the internal cooling system 234 may include one or more internalcooling chambers 236 having an internal volume less than one half of avolume of outer walls 242 forming the converging flow joint insert 120.One or more exhaust orifices 238 may extend from an inlet 240 in theinternal cooling chamber 236 through the outer wall 256 forming thefirst section 220 of the converging flow joint insert 120. The firstsection 220 may have a uniform thickness from the first side 222 to thesecond side 224 opposite to the first side 222. One or more exhaustorifices 238 may extend from an inlet 240 in the internal coolingchamber 236 through an outer wall 242 forming a second section 226 ofthe converging flow joint insert 120. The second section 226 may extendfrom the first section 220 and may form an outer downstream tip 228 ofthe converging flow joint insert 120. The second section 226 may have anonuniform thickness with a thickness at the outer downstream tip 228being less than a thickness at an upstream edge 230 of the secondsection 226.

In another embodiment, as shown in FIGS. 38-46, the transition ductsystem 100 may have an alternative configuration. The transition ductsystem 100 may include the first and second transition duct bodies 126,128 as previously set forth, but may include an alternativeconfiguration for the converging flow join insert 120. The transitionduct system 100 may include converging flow joint insert 120 positionedwithin a recess 300 at a downstream end 302 of the converging flow joint196 to form a trailing edge 301 of the converging flow joint 196. Therecess 300 may be positioned within the converging flow joint 196 andmay be configured to receive and house the converging flow joint insert120. In this embodiment, the converging flow join insert 120 may extendthrough the outer wall 202 at a downstream end 204 of the convergingflow joint 196. Instead, the converging flow join insert 120 may becontained completely within the recess 300 with a portion exposed toform the trailing edge 122 of the converging flow joint 196.

The transition duct system 100 may be held in place within the recess300 via an insert attachment system 303 configured to attached theconverging flow joint insert 120 to the converging flow joint 196. In atleast one embodiment, the insert attachment system 303 may be formedfrom one or more pins 304 extending into the converging flow jointinsert 120 and into the converging flow joint 196. In at least oneembodiment, the insert attachment system 303 may include one or morepins 304 extending through the converging flow joint insert 120 andthrough the converging flow joint 196. The insert attachment system 303may include one or more collars 306 for securing a first end 308 of thepin 304. The collar 306 may be integrally formed with the pin 304 or maybe attached to the pin via welding or other appropriate method. A secondend 310 of the pin 304 that is generally on an opposite end of the pin304 relative to the first end 308 may or may not include a collar 306.The pin 304 near the second end 310 may be secured to the convergingflow joint 196 via welding or other appropriate method.

The transition duct system 100 may include an internal cooling system312 within the converging flow joint insert 120. The internal coolingsystem 312 may include one or more internal cooling chambers 314 influid communication with one or more exhaust orifices 316 extending froman inlet 318 in the internal cooling chamber 314 through an outer wall320 forming the converging flow joint insert 120. The exhaust orifice316 of the internal cooling system 312 may include one or more exhaustorifices 316 extending from the internal cooling chamber 314 to anexhaust outlet 322 at an outer surface 324 facing a surface 326 formingthe recess 300 in which the converging flow joint insert 120 resides.The internal cooling system 312 may also include one or more exhaustorifices 318 extending from the internal cooling chamber 314 to exhaustoutlets 330 at an outer surface 332 facing downstream and away from therecess 300 in which the converging flow joint insert 120 resides.

In at least one embodiment, a portion of the internal cooling system 312may be contained within the pin 304 forming at least a portion of theinsert attachment system 303 configured to attached the converging flowjoint insert 120 to the converging flow joint 196. The pin 304 mayinclude an inner channel 334 having at least one inlet 336 positionedoutside of the recess 300 at the downstream end 204 of the convergingflow joint 196 and may include one or more exhaust outlets 338 in fluidcommunication with an internal cooling chamber 340. In at least oneembodiment, the pin 304 may include a first inlet 342 at a first end 344of the pin 304 in communication with the inner channel 334 in the pin304 and may include a second inlet 346 in a second end 348 of the pin304 at an opposite end of the pin 304 from the first end 344. Theconverging flow joint insert 120 may include a body 350 including anouter section 352, an inner section 354 and a middle section 356 betweenthe outer and inner sections 352, 354. The middle section 356 may have across-sectional area narrower in width than cross-sectional areas of theouter and inner sections 352, 354. The inner section 354 may extendfurther downstream than the middle section 356, and the outer section352 may extend further downstream than the inner section 354. Across-sectional area at a distal end 358 of the outer section 352 may belarger than a cross-sectional area at a distal end 360 of the innersection 354, as shown in FIG. 43.

In at least one embodiment, the converging flow joint insert 120 of theconverging flow joint 196 may be essentially load free when positionedwithin the converging flow joint insert receiver 136. In anotherembodiment, the converging flow joint insert 120 of the converging flowjoint 196 may be formed from a material having a larger coefficient ofthermal expansion than a material forming the converging flow jointinsert receiver 136. As such, during use when the converging flow jointinsert 120 and the converging flow joint insert receiver 136 are exposedto the hot combustion gases, the converging flow joint insert 120 willthermally expand at a faster rate than the converging flow joint insertreceiver 136. As such, the converging flow joint insert 120 will beplaced under at least a partial load formed from a compressive load,which partially alleviates the compressive load and stress placed on theconverging flow joint insert receiver 136 and surrounding structure. Theload and stress created in the converging flow joint insert 120 is lessthan at a trailing edge in a conventional system without a convergingflow joint insert 120. This is beneficial because stresses aretransferred from the permanent/high cost material forming the convergingflow joint insert receiver 136 and related components to the modular,disposable converging flow joint insert 120.

The foregoing is provided for purposes of illustrating, explaining, anddescribing embodiments of this invention. Modifications and adaptationsto these embodiments will be apparent to those skilled in the art andmay be made without departing from the scope or spirit of thisinvention.

What is claimed is: 1-
 15. (canceled)
 16. A transition duct system forrouting gas flow in a combustion turbine subsystem that includes a firststage blade array having a plurality of blades extending in a radialdirection from a rotor assembly for rotation in a circumferentialdirection, the circumferential direction having a tangential directioncomponent, an axis of the rotor assembly defining a longitudinaldirection, and at least one combustor located longitudinally upstream ofthe first stage blade array and located radially outboard of the firststage blade array, the transition duct system comprising: a firsttransition duct body having an internal passage extending between aninlet and an outlet; wherein the outlet of the first transition ductbody is offset from the inlet in the longitudinal direction and thetangential direction; wherein the outlet of the first transition ductbody is formed from a radially outer side generally opposite to aradially inner side, and the radially outer and inner sides are coupledtogether with opposed first and second side walls; a second transitionduct body having an internal passage extending between an inlet and anoutlet; wherein the outlet of the second transition duct body is offsetfrom the inlet in the longitudinal direction and the tangentialdirection; wherein the outlet of the second transition duct body isformed from a radially outer side generally opposite to a radially innerside, and the radially outer and inner sides are coupled together withopposed first and second side walls; wherein a first side of the firsttransition duct body intersects with a second side of the secondtransition duct body forming a converging flow joint; a recesspositioned within the converging flow joint; and a converging flow jointinsert positioned within the recess at a downstream end of theconverging flow joint to form a trailing edge of the converging flowjoint.
 17. The transition duct system of claim 16, further comprising aninsert attachment system configured to attach the converging flow jointinsert to the converging flow joint.
 18. The transition duct system ofclaim 17, wherein the insert attachment system comprises at least onepin extending into the converging flow joint insert and into theconverging flow joint.
 19. The transition duct system of claim 18,wherein the insert attachment system comprises at least one pinextending through the converging flow joint insert and through theconverging flow joint.
 20. The transition duct system of claim 18,wherein the insert attachment system further comprises at least onecollar for securing a first end of the at least one pin.
 21. Thetransition duct system of claim 16, further comprising an internalcooling system within the converging flow joint insert.
 22. Thetransition duct system of claim 21, wherein the internal cooling systemcomprises at least one internal cooling chamber in fluid communicationwith at least one exhaust orifice extending from an inlet in theinternal cooling chamber through an outer wall forming the convergingflow joint insert.
 23. The transition duct system of claim 22, whereinthe at least one exhaust orifice of the internal cooling systemcomprises at least one exhaust orifice extending from the at least oneinternal cooling chamber to an exhaust outlet at an outer surface facinga surface forming the recess in which the converging flow joint insertresides and at least one orifice extending from the at least oneinternal cooling chamber to an exhaust outlet at an outer surface facingdownstream and away from the recess in which the converging flow jointinsert resides.
 24. The transition duct system of claim 22, wherein atleast a portion of the cooling system is contained within a pin formingat least a portion of an insert attachment system configured to attachedthe converging flow joint insert to the converging flow joint.
 25. Thetransition duct system of claim 24, wherein the pin includes an innerchannel having at least one inlet positioned outside of the recess atthe downstream end of the converging flow joint and includes at leastone exhaust outlet in fluid communication with the at least one internalcooling chamber.
 26. The transition duct system of claim 25, wherein thepin includes a first inlet at a first end of the pin in communicationwith the inner channel in the pin and includes a second inlet in asecond end of the pin at an opposite end of the pin from the first end.27. The transition duct system of claim 16, further comprising a body ofthe converging flow joint insert includes an outer section, an innersection and a middle section between the outer and inner sections. 28.The transition duct system of claim 16, further comprising a body of theconverging flow joint insert includes an outer section, an inner sectionand a middle section between the outer and inner sections, wherein themiddle section has a cross-sectional area narrower in width than theouter and inner sections.
 29. The transition duct system of claim 28,wherein the inner section extends further downstream than the middlesection and the outer section extends further downstream than the innersection.
 30. The transition duct system of claim 28, wherein across-sectional area at a distal end of the outer section is larger thana cross-sectional area at a distal end of the inner section.